Spark plug



Sept. 2. 1924.

J. W. JACKSON SPARK PUG Filed sent. 30. i921 Patented Sept. 2, 1924.

JOHN WILLIAI'TJACKSON, OF EAST TAUNTON, MASSACI-ISETTS.

SPARK PUG.

Application filed September 30, 1921.

To aZZ 107mm t may Gomera:

Be it known that I, .lol-;N V. JACKSON,

a citizen of the United States, residing at East Taunton, in the county of Bristol and State of Massachusetts, have invented a new and useful Spark Plug, of which the following is a specification.

This invention aims to provide a simple means whereby an operator by inspection, can ascertain any time whether or not a spark plug` is worl'iing.

It is within the province of the disolosure to improve generally and to enchance the utility of devices of that type to which the invention appertains.

lVith the above and other objects in view, which will appear as the description proceeds, the inven-tion resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that, within the scope of what is claimed, changes in the precise embodiment of the invention shown can be made without departing from the spirit of the invention.

In the accompanying drawings:-

Figure 1 shows in elevation, a device constructed in accordance with the invention; 11`igure 2 is a longitudinal section on the line 2-2 of Figure 1; Figure 3 is a fragmental section on 'the line of Figure 2.

The spark plug forming the subject matter of this invention includes a body 1 provided at one end with threads 2 and supplied at its outer end with threads 3, the body having, intermediate its ends, a wrench head 4. In the inner end of the body 1 there is a passage 5 communicating with an enlarged Chamber 6 located in the upper end of the body. A shoulder 7 is formed at the place of juncture between the passage 5 and the chamber 6.

The numeral 8 denotes the core of the plug, the core being received, in part, in the passage 5 and in the Chamber 6. The core Szhas a sho'ulder 9 adapted to cooperate with the shoulder 7 of the body 1 of the plug. The core 8 is supplied with an outer' shoulder 10. A packing gasket 12 surrounds the core 8 and rests on the shoulder 10. A first electrode 14 is located in the core 8 and is provided at its outer end with an enlargement 15, passing through a washer 16 mounted on the end of the core.

Serial No. 504,353.

A binding nut 17 is threaded on the part 16 of the electrode 14 and cooperates with the washer 16. A second electrode 18 is located in the core 8. The inner end 19 of the electrode 18 preferably is extended toward the inner end of the first electrode 14. The outer end of the second electrode 18 is extended laterally, as shown at 20, in a direction substantially at right angles to the axis of the plug. In the side wall of the core 8, a transverse bore 21 is formed. A packing disk 22 is seated in the inner end of the bore 21. The numeral 23 denotes a tubular guard, preferably made of glass. One end of the guard 23 is received in the bore 21 and abuts against the packing disk 22. The end 20 of the electrode 18 extends into the guard 23.

The numeral 24 marks a retainer including a flange 25 and a head 26, the retainer having wrench surfaces 27. The fiang'e 25 of the retainer 24 is threaded on the part 3 of the body 1, the head 26 of the retainer engaging the packing gasket 12 and compressing the same, to secure a water' tight joint, and compress the shoulder 9 of the core 8 against the shoulder 7 ofl the body 1. The reta-iner 24 is provided with an ear 28 in which an adjustable terminal 29 is mounted. The terminal 29 preferably is in the form of a screw threaded into the ear 28. The screw or lterminal 29 extends into the tuloular guard 23, the outer end of the `guard 23 being in close relation to the inner surface of the ear 28.

lVhen the plug is working properly, a spark will always occur between the end 20 of the electrode 18 and the terminal 29, and since this spark can be observed through the guard 23, the operator can ascertain at a glance, the condition of the plug. The terminal 29 may be advanced or ret'racted so as to cooperate properly with the part 20 of the electrode 18. It is to be observed that the screw or terminal 29 enters the outer end of the guard 23 and constitutes a closure therefor.

lVhat is claimed is In a device of the class described, a. sparr plug comprising a body; a core in the body and having a recess; a retainer threaded on the body and en-gaging the core; a tube eX- tended between a portion of the retainer and the core and received in the recess of the core; a screw threaded into said po-rt'io-n In testimony that I claim the foregoing of the retainer and entering the tube; and as my own, I have hereto affixed my signaan electrode in the core and extended into ture in the presence of two wtnesses.

the tube, into jump spark relation with re- JOHN VILLIAM JACKSON. spect to the screw, and another electi'ode VVitnesses:

Inounted in said core for Cooperation With THOMAS H. SHERRY,

the first mentioned electrode. J ULIA F. CAMPBELL. 

